Nonshrinkable textile material



H. R. HAERTEL 1,928,355 NONSHRINKABLE TEXTILE MATERIAL Sept. 26, 1933.

Filed Jan. 15, 1931 Inven77or: Hans 11/. Hwez'iel. 5 A31. r

Patented Sept. 26, 1933 UNITED STATES PATENT OFFICE 3 Claims.

My invention relates to flexible textile material resistant to watershrinking, and to methods of making the same, adapted for use, forexample, in connection with automobile tops and for other purposes whereit is subjected to alternate wetting and drying.

The invention will be best understood from the following descriptionwhen read in the light of the accompanying drawing of one embodiment ofmaterial according to the invention and of one example of the practiceof a method of making the material, while the scope of the inventionwill.

be more particularly pointed out in the appended claims.

In the drawing:-

Fig. l is a plan of an idealized much magnified fragment of the materialwith parts broken away; and

Fig. 2 is a section on the line 22 of Fig. 1.

As illustrated, the material comprises outer textile sheets 1 and 3united by a thin, flexible layer comprising a middle textile sheet 5embedded in rubber compound so as to face said middle sheet with layersof compound 7 and 9 uniting the outer textile sheets to said middletextile sheet. As illustrated, the threads of the two outer sheets,particularly the warp threads 11, are deeply embedded in the compound,but without the compound extending through the meshes 13 defined byadjacent warp threads and weft threads 15. As illustrated, the rubbercompound at opposite sides of the middle sheet 5 bears the same rela-'tion to the threads of said middle sheet, but if desired, and preferablyin some cases, 'the compound may extend entirely through the meshes ofsaid middle sheet.

It will be observed that the textile sheets-at opposite sides of thematerial after being incorporated therein have their original appearanceand feel" without any alteration in these properties due to the rubberextending through the meshes. It will also be observed that the 5 middlesheet is entirely waterproofed by the 45 rubber compound, in consequenceof which wetting of one or both of the outer sheets will not beeffective to wet the inner textile sheet, with the result that only theouter sheets are subjected to water shrinking.

It has been found that if rubber compound is applied to the sheets bythe usual "calendering or spreader process, or if the usual rubbercompound for uniting textiles is employed, the material is subject towater shrinking. This is believed to be due to the-low tensile strengthof the usual rubber compound, and to the fact that when sheets are notmaterially embedded in the compound, with the result that when the outersheets are subjected to water shrinking, the middle sheet will becompressed in the plane of said sheet, and minute slippage will occurbetween the outer sheets and the rubber compound at a multitude ofpoints, as will likewise occur minute shearing of the rubber compound atsaid points, with the total effect that the material will water shrinkand be much distorted.

The improved product is characterized by the use of rubber compound ofhigh tensile strength in which the threads of the outer sheets,particularly the warp threads, are deeply embedded, thus preventingshearing of the rubber and slippage of the outer sheetsrelative to therubber, while this rubber compound of high tensile strength fills themeshes of the middle sheet to such an extent as to render said middlesheet substantially incompressible in the plane of said sheet. It willtherefore be observed that the two outer sheets are united by a stronglyadhering, incompressible layer of material. In this aspect the middlesheet constitutes fibrous material contained in the rubber compound formaking the layer uniting the outer sheets incompressible.

As a practical example of a method of making the material, but withoutlimitation thereto, the outer sheet 1 may be coated with a layer ofrubber by use of hot calender rolls in the usual manner, except that thepressure between the rolls is much greater than that ordinarily employedand is sufficient with respect to the consistency of the hot rubbercompound to force the latter slightly less than half way through thetextile. One side of the middle sheet 5 may be likewise calendered,after which the sheets 1 and 5 may be doubled, which is to say, they maybe placed with their rubberized sides in contact and united by passingthem between rolls. The united sheets 1 and 5 may then be passed throughthe calender roll and a layer of rubber compound applied to the exposedside of the sheet 5, which, if desired, may entirely fill the remainingportions of the meshes of the textile, it being observed that the layerof rubber 7 at that time between the sheets 1 and 5 is cooled and isrelatively hard and therefore is not forced farther into said sheets,while the rubber being applied to the exposed side of the sheet is hotand therefore relatively soft. A layer of rubber may now be applied toone side of the sheet 3 in the same manner as above described in noconnection with the sheet 1, after which the doubled sheets 1 and 5 maybe doubled with the sheet 3. The material may then be cured.

As an example of the textile, but without limitation thereto,satisfactory results have been secured with teal cloth of plain weaveweighing 12.4 lbs. per square yard with 52 two-ply yarn warp threads perinch and 38 single-ply yarn weft threads per inch, this material being acommon material for use in connection with automobile tops. v

The rubber compound may be given a high tensile strength in any suitablemanner known to those skilled in the art. Conveniently this may be doneby use of a large percentage and volume of rubber, the large volume ofrubber secured by use of relatively heavy fillers such as bariumsulphate, lithopone, etc., instead of the much lighter whiting morecommonly employed. Also to avoid sticking of the compound to thecalender rolls, due to the presence of a high percentage of rubber,conveniently the compound may contain a small percentage of wax, such asMontan wax, and conveniently to give the rubber a wide variation insoftness when it is hot compared to when it is cold the compound maycontain small percentages of resins such as ester gum, cumarone resin,indene resin, etc. With theabove cloth satisfactory results have beensecured by applying 7 ounces per square yard at each of the abovedescribed calendering operations of rubber compound having the followingconstituents:-

Pounds Pure rubber milled with accelerator and anti-oxidant 10 Purerubber 30 Reclaimed rubber 40 Montan wax 2.8 Zinc oxide (activator) 6Lithopone (mixture of zinc sulphide and barium sulphate constituting anopaque heavy filler) 10 Barium sulphate (heavy filler) 26 Whiting 15Zinc stearate 1 Magnesium oxide (acid neutralizer) .5 Sulphur(vulcanizing agent) .94

Cumar (mixture of cumarone and indene resins) 2 It will be realized thata non-shrinkable material, such as herein described, for economicconsiderations is highly desirable from the aspect of both themanufacturer and user. It will be understood that it is unnecessary toshrink the improved material after curing to render it resistant towater shrinking, and that therefore an appreciable economic saving iseffected, for if it were necessary to shrink the material, and thisshrinkage were say 5 which is not excessive in respect to priorproducts, a loss to the manufacturer of 5 yards per hundred yards ofmaterial would occur, which ordinarily would represent a loss of fromfive to ten dollars per hundred yards of material. From theseconsiderations it therefore will be observed that with a mill producingsay 2000 yards of material daily, the improved product in respect toshrinkage will effect a saving of from five hundred to one thousanddollars daily.

From the aspect of the user, say an automobile manufacturer, theimproved material has the advantage that, when employed, no allowanceneed be made for water shrinking, this allowance resulting in anunsightly appearance of the automobile top, whereas if allowance forwater shrinking is not made, the latter when it occurs will causedistortion of the top, and, in extreme cases, breakage of the bows ofthe top framework.

It will be understood that except as defined by the appended claims theinvention is not limited to the use of any particular textile orparticular ingredient of the rubber compound, and that wide deviationsmay be made from the product, and method of making it, herein describedwithout departing from the spirit of the invention.

I claim:

1. Flexible material comprising two exposed textile sheets which arecharacterized by the property of water shrinking and are joined by astrongly adhering, interposed layer comprising rubber compound andfibrous material, the latter rendering said layer substantiallyincompressible in the plane of said layer for resisting water shrinkingof said sheets.

2. Flexible material comprising two exposed textile sheets which arecharacterized by the property of water shrinking and are joined by astrongly adhering, interposed layer which inherently is substantiallyincompressible in the plane thereof, said layer comprising a textilesheet treated with layers of rubber compound of high tensile strength,in which compound the threads of said exposed sheets are embeddedwithout said compound extending through the meshes thereof.

3. Flexible material resisting water shrinking comprising three closelyadjacent textile sheets which are characterized by the property of watershrinking, the outer sheets being joined to the middle sheet byinterposed, strongly adhering, relatively thin layers of rubber compoundof high tensile strength, said compound sufliciently filling the meshesof said middle sheet to render is substantially incompressible in theplane of said sheet, the threads of said outer sheets being embedded insaid compound without the latter ex tending through the meshes thereof.

HANS RICHARD HAERTEL.

